 It is infinitely difficult to know when and where one should stop, and for all but one in thousands the goal of their thinking is the point at which they have become tired of thinking.Letter to Moses Mendelssohn, January 9, 1771

 The melancholy science from which I make this offering to my friend relates to a region that from time immemorial was regarded as the true field of philosophy, but which, since the latter’s conversion into method, has lapsed into intellectual neglect, sententious whimsy and finally oblivion: the teaching of the good life. What the philosophers once knew as life has become the sphere of private existence and now of mere consumption, dragged along as an appendage of the process of material production, without autonomy or substance of its own.E. Jephcott, trans. (1974), Dedication

 If we would have killed 10.3 million Jews, then I would be satisfied and would say, good, we annihilated an enemy. ... I wasn't only issued orders, in this case I'd have been a moron, but I rather anticipated, I was an idealist.Post-war correspondence with Willem Sassen om Eichmanns Memoiren. Ein kritischer Essay (Zuerst 2001) Frankfurt/M.: Fischer TB, 2004 ISBN 3-5961-5726-9

 In quantum physics, however, each observation implies an intervention in the observed. Because of the quantum physical laws of nature, a change of state of the observed is inevitably coupled to the observation process. So it's not a situation independent from the experiment that is observed, but we ourselves call forth the facts (or compel them to go in a certain direction to a disambiguation), that then become an observation.Quantenmechanische Bemerkungen zur Biologie und Psychologie, Erkenntnis, Vol. 4 (1934). p. 228.

 It is so easy to be immature. If I have a book to serve as my understanding, a pastor to serve as my conscience, a physician to determine my diet for me, and so on, I need not exert myself at all. I need not think, if only I can pay: others will readily undertake the irksome work for me.

 Translation: And therefore I wish, that in 50 years the citizens of Europe will say: At that time, in Berlin, the united Europe has set the course correctly. At that time, in Berlin, the European Union has pursued a good future. Then it has renewed its fundamentals to make its contribution inwards, on this old continent, as well as outwards, in this big-small world.Speech at the 50th anniversary of the signing of the Treaties of Rome on March 25, 2007

 Model for others. He who wants to set a good example must add a grain of foolishness to his virtue; then others can imitate and, at the same time, rise above the one being imitated - something which people love.Section IX, "Man Alone with Himself" / aphorism 561.

 There is only one healing force, and that is nature; in pills and ointments there is none. At most they can give the healing force of nature a hint about where there is something for it to do.Neue Paralipomena

 Any progress in the theory of partial differential equations must also bring about a progress in Mechanics. Carl Gustav Jacob Jacobi Vorlesungen über Dynamik [Lectures on Dynamics] 1842/3; publ. 1884

 "In Pliny, whom one could call, if not a Spinozist, then perhaps a Pandeist, Nature is not a being divided off or separated from the world. His nature is the whole of creation, in concrete, and the same appears to be true also of his divinity." Gottfried Große, Naturgeschichte: mit erläuternden Anmerkungen (Natural History: With Annotations; translation and interpretation of Pliny the Elder's Natural History), 1787, page 165. This is the earliest extant description of pandeism found to date.

 Day thrust its brightness through the window-pane.They, locked together, strove to keep Day outAnd could not, whence they grew aware of dread.She, his beloved, casting her arms aboutHer loved one, caught him close to her again.Her eyes drenched both their cheeks. She said:"One body and two hearts are we." "Den Morgenblic bî Wahtærs Sange Erkôs", line 11; translation in Margaret F. Richey Essays on Mediæval German Poetry (Oxford: Basil Blackwell, 1969) p. 99.